Exogenous administration of mitochondrial DNA promotes ischemia reperfusion injury via TLR9-p38 MAPK pathway
Exogenous administration of mitochondrial DNA promotes ischemia reperfusion injury via TLR9-p38 MAPK pathway
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外源性给予线粒体DNA通过TLR9-p38 MAPK通路促进缺血再灌注损伤
DOI：
10.1016/j.yrtph.2017.07.028
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发表时间：
2017-10-01
影响因子：
3.4
通讯作者：
Gong, Jianbin
中科院分区：
文献类型：
--
作者：
Xie, Liang;Liu, Shuyu;Gong, Jianbin
先前的研究已经表明线粒体DNA （mtDNA）在先天免疫中的作用。然而，mtDNA在急性心肌梗死中的具体作用尚不清楚。本研究旨在检测mtDNA对心肌细胞的破坏作用。H9c2s细胞与纯化的mtDNA或核DNA孵育，并使用或不使用toll样受体9（TLR9）抑制剂氯喹预处理。MTT法检测细胞活力。为了验证mtDNA的毒性，在大鼠缺血前10分钟注射mtDNA片段30分钟，再灌注24小时，用TTC染色法测定梗死面积。TUNEL染色检测心肌细胞凋亡及caspase-3活性。western blotting检测TLR9、p-p38 MAPK、p38 MAPK水平。结果表明，外源mtDNA降低H9c2s细胞活力，诱导TLR9表达、caspase 3活化和p38丝裂原活化蛋白激酶（MAPK）磷酸化。然而，这些作用被氯喹所抑制。相比之下，核DNA没有这些影响。大鼠静脉注射mtDNA通过激活TLR9-p38 MAPK，加重缺血再灌注损伤，增加梗死面积。我们认为AMI释放到循环中的mtDNA可能通过TLR9-p38 MAPK通路加重心肌缺血再灌注损伤，从而对心肌产生不利影响。(C) 2017年Elsevier Inc.出版。
Previous studies have shown a role of mitochondrial DNA (mtDNA) in innate immunity. However, the specific role of mtDNA in acute myocardial infarction remains elusive. This study was designed to examine the damaging effect of mtDNA on cardiomyocytes. H9c2s cells were incubated with purified mtDNA or nuclear DNA with or without pretreatment by chloroquine, an inhibitor of Toll-like receptor 9(TLR9). The cell viability was tested by MTT. To demonstrate the toxicity of mtDNA, mtDNA fragments were injected into rats 10 min before ischemia for 30 min and reperfusion for 24 h. Infarct size was measured by TTC staining. Apoptosis of myocardium was detected by TUNEL staining and caspase-3 activity. The levels of TLR9, p-p38 MAPK, and p38 MAPK were detected by western blotting. The results showed that exogenous mtDNA reduced the viability of H9c2s cells and induced TLR9 expression, caspase 3 activation and p38 mitogen-activated protein kinase (MAPK) phosphorylation. However, these effects were inhibited by chloroquine. In contrast, nuclear DNA did not have these effects. Intravenous injection of mtDNA into rats aggravated ischemia-reperfusion injury and increased infarction area through TLR9-p38 MAPK activation. We concluded that mtDNA released into the circulation by AMI may has detrimental effect on myocardium through aggravating ischemia-reperfusion injury via TLR9-p38 MAPK pathway. (C) 2017 Published by Elsevier Inc.